Episode 91: Toxicology Results - What Does the Number Actually Mean?

So interpreting results in toxicology is hard.

And many of us know that it's really challenging.

Lots of different factors need to be considered.

like observed clinical effects, the circumstances surrounding the case, individual drugs and drugs in combination.

So the big question is, does detecting a drug in toxicology actually mean someone has been poisoned?

And I think that this is the CSI generation.

Yeah, I feel like that's...

We'll see dramatised versions of, oh, we've detected X and therefore Y, or the other way around.

Yeah.

And you're right.

How often do we look at drug results or poison results and have to make a judgment call as to whether it's significant or not?

And there are a couple of opposing biases that also come into play when interpreting toxic results.

So one is the unproven ingestion bias.

So this is instances where studies claim toxicity in the absence of confirmatory lab testing.

So there's a couple of quite famous-ish examples of this.

It often occurs in pediatric patients where exposure is suspected but was never witnessed.

For example, Dr.

Levy evaluated this bias in a poison control center of children suspected to have ingested methanol, ethylene glycol, and only 20.6% of all the patients actually had positive toxic alcohol levels detected.

And it was assumed based on their presentation that these particular toxins had caused this issue.

So I've definitely had cases where children were found in the presence of a bottle of antifreeze.

Yeah.

And therefore, testing was carried out.

Now, in defence of anybody working in paediatric ED in that situation, A, ethylene glycol is really, really sweet tasting.

Yeah.

And I'm told children do like to drink it, although it must have bittering agents put in to commercial